Improvement in tubular air-heaters



=B, R. HAWLEY.

Hot-Air Furnace.

No; 81,781; Pate'ntd Sept. 1, 1868.

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B. B. HAWLEY, OF NORMAL, ILLINOIS.

IMPROVEMENT IN TUBULAR AIR-HEATERS.

Specification forming part of Letters Patent N 0. 81,781, datedSeptember 1, 1868.

To all whom it may concern:

Be it known that I, B. R. HAWLEY, of Normal, in the county of McLean andState of Illinois, have made certain new and useful Improvements inTubular Air-Warmers; and I do hereby declare that the following is afull and clear description thereof, reference being had to theaccompanying drawings, and to the letters of reference marked thereon.

The object of this invention is to warm air very rapidly for heatingbuildings and other like purposes. To accomplish this result aheating-furnace, not altogether unlike a locomotive-boiler, is used, andthe air to be heated is passed through the interstices between thetubes, and is there heated very rapidly and economically.

The peculiar details of the invention will more fully appear from thefollowing description.

To enable those skilled in the art to make and use my improvedair-Warmer, I will proceed to describe its construction and operation.

Figure 1 of the drawings is a sectional elevation of the improvedapparatus. Fig. 2 is a sectional plan of the same, taken on the line m yof Fig. 1. Fig. 3 is a transverse sectional elevation taken on the line00' y of Fig. 1.

The walls A of this furnace may be constructed of sheet metal, and theywill inclose within them the fire-box'B in such a manner as to leave anarrow heatingchamber, b, between the said outer wall A and fire-box B.This heating-chamber will inclose the fire-box on all sides, except thatoccupied by the door a, through which fuel is fed to the furnace. Thechamber b will be in open communication with the chamber b, as is shownin Fig. 2, Longitudinal flues or tubes 13 extend from the rear wall ofthe fire-box to the bridge-wall A through the top part of the "chamberb.A rear breeching, O, connects the bottom flues B with the top ones B andthe forward breechin g G connects the top flues B with the horizontalsmoke-flue D, and this discharges the smoke into the stack D. The smokefrom the furnace escapes with the hot gases in the direction of thearrows 0, through the tubes B, into the breechin g G, and thence backthrough the tubes B and so on through the breechin g G and flue D intothe stack D.

The cold air is allowed to enter the chambers b and 11 through openingsat a, as shown in Fig. 2. As the cold air rises in the chamber b' itbecomes rapidly heated by its immediate contact with the plates of thefirebox, and that rising from the chamber 7) passes through theinterstices between the tubes B and B, and in like manner becomesheated, as may\be required. Both volumes become mingled in the chamberE, whence the heated air may be taken off through the perforated plate Eto heat any apartment; or it may be taken off to distant places in pipesin the usual manner.

The doors 0 c in the breechings O G and of the fire-box, is corrugated,as shown in Fig.

3, and that portion of it which forms the diaphragm between the fire-boxand the chamber of the breeching O is perforated at 11 for the purposeof allowing the flames from the incandescent fuel within the iirebox topassthrough the said perforations and ignite the soot and smoke at thatpoint, thereby not only serving to keep the breeching and flues freefrom soot, but also greatly economizing fuel by consuming the otherwisewasted carbon of the smoke.

Having described my invention, what .I':

claim is- The diaphragm B, when perforatedat b and otherwise arranged,as herein shown and

